Ugh...
The best way would have been to have picked up your truck there - assuming of course you bought it new. Cause then they DO put you in an X6M! (Which really kind of sucks if you are picking up a 50 or 35 cause you get in your car and say "chit, I thought this thing was faster"
)
I do know that if you are a member of the BMW CCA, you can get a discount (and if you bought your car new and were a member you would have received a $1K check from BMW). I also know they put these classes on sale.
The last thing I'm well aware of is that I've never met a single person who did not think it was worth every damn penny. It is an AMAZING experience (I just did the 1 day M school that came with my M5 as well as the delivery experience with my X6) - but even then, I would have no hesitation going back. The biggest challenge is that once you have finished the M school is that you are going to want to go to the VIR school which I hear is even better and possibly more expensive.
Do it.